/Engine/Plugins/Experimental/Fracture/Source/FractureEngine/Public/FractureEngineClustering.h
Merge any partitions w/ only 1 body into a connected, neighboring partition (if any). This can decrease the number of partitions below the desired count.
void MergeSingleElementPartitions ( [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) * GeometryCollection )